Process of dry adhesive-free thermal transfer of indicia

ABSTRACT

A process and composition are provided that provide for thermal transfer of ink compositions and eliminate the need to prepare articles such as sign faces, particularly flexible sign faces, by painting with ink compositions that contain solvents. The present process and composition permit thermal transfer from a carrier to a receptor at low temperatures with the use of vacuum pressure. The transferred ink adheres tenaciously to the receptor and is flexible.

This is a continuation of application Ser. No. 296,491 filed Aug. 26,1981 which was a continuation of application Ser. No. 163,643 filed June27, 1980 both now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to thermally-transferable ink compositions, andprocesses for transferring a dry layer of a thermally-transferable inkcomposition from a carrier to a receptor. The present invention isparticularly useful in manufacturing sign faces by transferring indiciafrom a carrier to a receptor in a completely dry process.

Past techniques for manufacturing sign faces have not proven entirelysatisfactory. For example, these techniques have involved masking oroutlining the surface of the sign face so as to provide a desiredoutline, followed by painting (e.g., by brushing or spraying) to obtainthe desired colored design. Such techniques are time consuming, messy,and require that steps be taken to provide adequate ventilation for thehazardous solvents employed with the paints or inks. Moreover, stepsmust be taken to insure that the solvents used in the inks do notdestroy the surface to which they are applied. Furthermore, such priorart techniques frequently require that various inks be mixed. This, ofcourse, means that a color match must be made before the mixed ink canbe utilized.

Processes for thermally transferring indicia from a carrier (e.g.,release liner) to a receptor (e.g., a fabric such as cotton) andcomposition useful therewith are also known. See for example U.S. Pat.Nos. 3,361,281; 3,519,463; 3,684,545; 3,928,710; and 4,037,008. Theseprocesses and compositions generally require the use of high heat andpressure to effect transfer. Typically temperatures of 120° C. or moreare required.

The use of the foregoing processes has not proven entirely satisfactory.For example, the temperatures employed require the use of largequantities of energy and limit the number of materials that can beutilized as receptors as the heat generated may degrade certainpolymeric receptors. Still further, these prior art processes have notbeen found to provide strongly adhered images on uneven or textured andthree dimensional substrates. Consequently, it is clear that a needexists for compositions, and processes for transferringthermally-transferable inks that overcome these disadvantages.

SUMMARY OF THE INVENTION

Provided herein are a novel process and composition that provides uniqueresults. The process comprises a dry technique for transferring athermally-transferable ink composition from a carrier to a receptor.This process eliminates the need to employ adhesives to bond the ink tothe receptor. It also eliminates the need to go through the timeconsuming and potentially hazardous techniques described above.Furthermore, it eliminates the need for the sign fabricator to employvolatile solvents in sign preparation. Still further, the processprovides the sign fabricator with almost unlimited versatility in thedesign of the artwork to be utilized on the sign face. Consequently, thefabricator can employ a wide variety of colors and decorative designs onthe sign face.

The process of the invention comprises the steps of

(a) providing a carrier bearing a thermally-transferable inkcomposition;

(b) applying said ink to a receptor surface;

(c) adjusting said receptor surface so that it is free from wrinkles;

(d) evacuating substantially all of the air from the interface betweensaid ink and said receptor surface;

(e) heating said ink and said receptor surface to a temperature, and fora time, sufficient to soften said ink and intimately bond it to saidreceptor, said heating occurring after substantially all of said air hasbeen evacuated from said interface.

The novel composition provided herein is particularly preferred for usewith the above-described process. It comprises a thermally-transferableink composition having a 20% elongation temperature of less than 85° C.and an elongation at break of at least about 15%. The ink is made up of

(a) from about 50 to 95% by weight of a thermoplastic polymer selectedfrom the group consisting of polyvinyl chloride and copolymers thereof;

(b) from about 50 to 5% by weight of a flexibilizer for saidthermoplastic polymer that is compatible with said thermoplasticpolymer; and

(c) up to about 40% by weight of a colorant.

Sign faces made by utilizing the novel process and composition describedherein offer several advantages. For example, the ink compositionsconform virtually exactly to the surface of the receptor. Thus, the inkcan be applied to textured substrates and be totally adhered thereto.

Still further, the inks of the invention can be utilized to fill-inopenings left for indicia in a previously applied layer. The inkconforms exactly to the surface and completely fills in the opening andbecomes totally adhered to the receptor. This is particularly useful inproviding indicia of one color on a differently colored background.

The conformability of the inks of the invention is of particularsignificance in the preparation of large are flexible sign faces. Thesesign faces typically require that two or more sheets of the receptor bejoined or seamed together. Each juncture or seam is thicker than anindividual sheet of the receptor so that a mound or ridge is formed. Theinks of the invention conform and adhere to both the seam and thebalance of the receptor tenaciously.

This excellent adhesion and conformability is surprising, particularlywith respect to the most preferred aspects of the invention, since lowtransfer temperatures are employed during the process. Furthermore, inktransferred in accordance with the present invention exhibit excellentflexural characteristics. Thus, when a completed pliant sign face isflexed, the ink does not crack or peel off. Moreover, when completedrigid sign faces expand and contract due to temperature changes, the inkdoes not rack or peel off.

Still further, the ink compositions of the invention exhibit excellentweatherability. For example, they do not show any significant fading ordarkening when exposed to outdoor conditions. Moreover, they do notchip, peel, crack, etc. under these conditions.

The adhesion of the transferred ink to the receptor is demonstrated bythe tape adhesion test described in ASTM D 3359-74, method B with themodification that the receptor is 0.5 mm thick.

In the tape adhesion test, a lattice cut is made so as to provideintersecting cut lines through the ink layer and into the receptor.Pressure sensitive tape is applied over the lattice and then strippedaway. The ink compositions of the invention exhibit a classificationnumber of at least 4, and preferably 5. A classification number of 4means that virtually none of the transferred ink is removed while aclassification number of 5 means that none of the transferred ink isremoved.

DETAILED DESCRIPTION OF THE INVENTION

In the process of the present invention, a thermally-transferable ink istransferred from a carrier to a receptor at a temperature sufficient tosoften the ink and intimately bond it to the receptor. While anytemperature sufficient to achieve this result may be utilized, thetemperature is preferably in the range of 75° C.-110° C., and mostpreferably in the range of 85° C.-95° C.

The essential steps of the process of the invention are set forth above.Thus, a carrier bearing a dry layer of thermally-transferable ink(hereinafter referred to as the "transfer sheet") is placed on a desiredreceptor so that the ink contacts the receptor surface. Carriers andtechniques for applying the ink thereto will be described hereinafter.

While it is not necessary to the process, it is frequently desirable toprovide an image of the desired art work on the receptor prior toplacing the transfer sheet on the receptor. A variety of techniques maybe employed to do this. In one useful technique a reduced-size black andwhite photocopy of the sign face to be prepared is made. The photocopyis then utilized to make a projection transparency, which is thenprojected onto the desired receptor surface. The size of projected imagecan be readily adjusted so as to obtain the desired size of sign bytechniques known to the art.

The transfer sheet may be fastened to the receptor by a variety oftechniques. However, simply taping the transfer sheet is sufficient. If,it is desired to provide a differently colored background, that is acolor that is different than the color of the receptor, a transfer sheetof one color may be fastened to the portion of the receptor surfacedesired to be differently colored followed by removing (e.g., by cuttingout) the image areas from the transfer sheet. A second transfer sheet,having the color desired for the art work may then be fastened over thecut-out areas of the first transfer sheet.

Once the appropriately colored transfer sheets have been fastened to thereceptor, the resulting intermediate structure is placed in a device,such as a vacuum frame, and adjusted so as to provide a wrinkle freesurface. If necessary, this may be accomplished by placing theintermediate structure under tension.

A particulary advantageous technique for providing a wrinkle-freesurface is to turn on the vacuum pump of the vacuum frame with theintermediate on the vacuum bed thereof and with the top thereof up. Ifthe intermediate does not cover the entire vacuum bed, sheets ofsubstantially non-porous material may be placed over the uncoveredportions. Wrinkles in the intermediate may then be squeezed out orotherwise removed. The non-porous sheets may then be removed (leavingthe wrinkle-free intermediate) and the top lowered.

Typically the intermediate is placed in the vacuum frame so that thereceptor contacts the vacuum bed and the transfer sheeting contacts thetop when the top is closed. The exact vacuum frame utilized in theprocess of the invention is not critical to the invention as a varietyof commercially available vacuum frames are useful.

Preferably the vacuum bed of the frame has a smooth surface free fromridges, lumps, etc., especially where the perforated vacuum bed meetsthe outer supports of the vacuum frame. Additionally, the vacuum bed ispreferably covered with a porous material such as muslin.

The top of the vacuum frame contains an air bladder and, above thebladder, a lamp bank. The top is preferably hinged on one end and haslocks on the other end. The hinges and locks are located so that a widesheet of receptor can pass therebetween. A porous fabric, such asmuslin, is preferably fastened to the surface of the bladder thatcontacts the transfer sheet. The lamp bank preferably comprises aplurality of lamps that, preferably, emit radiation in the infra redrange. A temperature controller is also preferably included so as toregulate the heat input into the vacuum frame.

Once the wrinkles have been removed from the intermediate, the vacuumframe is closed and a vacuum created therein to evacuate substantiallyall of the air from the interface between the ink and the receptor andprovide intimate contact between the receptor and the ink. It has beenfound that this may be accomplished by reducing the pressure in theframe to between about 0.1 to 0.25 atmosphere for from 2 to 5 minutes.Preferably the pressure is reduced to at least about 0.2 atmosphere.

The receptor surface and the ink are then heated to the predeterminedtransfer temperature. Heating may be accomplished by a variety oftechniques, although it has been found that a bank of 300 wattincandescent light bulbs that emit radiation in the infrared range issatisfactory. The intermediate, particularly receptor surface and ink,is heated to a temperature sufficient to soften the ink and intimatelybond it to the receptor. The exact temperature is dependant upon thenature of the ink and the receptor employed. The temperature must,however, be below that at which the ink and receptor degrade.

During heating, the ink and receptor surface fused together and form anintimate bond. Preferably heating is carried on only for a timesufficient to accomplish this result. It has been found that, with thecompositions of the invention, heating need only be at a temperaturebetween about 75° to 110° C for from 2 to 10 minutes.

Evacuating substantially all of the air from the interface between thereceptor surface and the ink causes a pressure differential between theinterface and the exterior of the intermediate structure. The lack ofair at the interface in combination with the pressure differential makesit possible to achieve the tenacious and intimate bonding of the ink tothe receptor at low temperatures. Preferably the pressure differentialis at least about 0.75 atmosphere.

The vacuum is then released and the receptor and ink are cooled. Thismay be done by passive means or by active means, for example by blowingair over the intermediate. Once the intermediate has cooled to atemperature (e.g., a temperature of 65° C. or less) sufficient to hardenthe ink and cause the adhesion of the ink to the receptor to be greaterthan the adhesion of the ink to the carrier, the carrier is strippedfrom the receptor. The resultant receptor then bears indicia that arefirmly anchored thereto and that conform exactly to the surface thereof.

In the event that the receptor is too large to fit entirely within thevacuum frame at one time, the above described process may be repeated ina step-wise manner until the entire sign face has been completed. Duringa step-wise process it is preferred that indicia (e.g., letters,numbers, etc.) to be transferred be located entirely within the frameduring heating.

A wide variety of receptors may be utilized in the process of theinvention. They may be polymeric or non-polymeric, flexible or rigid,and thick or thin. Moreover, the surface of the receptor may be smoothor irregular.

Receptors useful with the present invention include a variety ofpolymeric films including polyvinylchloride (e.g., Panaflex® film fromNational Advertising Company and Scotchal® film from 3M Company),acrylic films (e.g., Plexiglass® from Rohm and Haas), cellulose acetatebutyrate film, and urethane films. Other resin films may also beemployed as receptor materials. The receptor materials may be used assuch or they may have their surface modified by, for example, priming,corona treatment, solvent wiping, etc.

The novel compositions described herein comprise a defined thermoplasticresin, a flexibilizer for said resin, and, optionally, a colorant, anultraviolet light absorber, a heat stabilizer, a surfactant, a flow aid,etc. They have a 20% elongation temperature of no more than about 85° C.and preferably one in the range of 70° C. to 85° C. Additionally, theyhave an elongation at break of at least 15%.

The 20% elongation temperature is determined in the same manner as thering and ball softening point described in ASTM E-2842-T except that thefilm thickness is 25 microns, the ball weight is 1.5 g, the ring widthis 14 cm, and heating is done in air and commences at 60° C. and israised at a uniform rate of 1.7° C. per minute. The 20% elongationtemperature is that temperature at which a film of the resin haselongated 120% of its original dimension.

Elongation at break is measured according to ASTM D412-75, Method A,section 12.2. Test samples are 1.25 cm wide with a spacing of 1.25 cm.Pulling speed is 10 cm per minute. The measurement of elongation atbreak is set forth at section 5.2 of the test method.

The ink compositions may be readily prepared by, for example, dissolvingthe thermoplastic resin and flexibilizer together in a suitablescreen-printing solvent, such as isophorone or cyclohexanone, followedby addition of the colorant and other ingredients. The colorant may beadded directly if a dye is used. If a pigment is used, it is firstpreferably dispersed in a solvent, resin, or plasticizer that iscompatible with the solvent used to dissolve the thermoplastic resin.Known processing techniques may be employed in preparing thecompositions.

The thermoplastic resins useful in the novel compositions comprise fromabout 50% to 95% by dry weight of the composition, and preferably fromabout 65% to 95% by dry weight. They are selected from polyvinylchloride and copolymers thereof. Specific examples include, for example,polyvinyl chloride, polyvinyl chloride-polyvinyl acetate copolymers(e.g., Bakelite®VYHH available from Union Carbide Company).

The flexibilizer employed in the novel compositions comprises from about50 to 5% by dry weight of the composition, and preferably from about 20to 5%. It flexibilizes the composition and is compatible with the vinylpolymer or copolymer. Moreover, it imparts conformability and elasticityto the ink composition, and improves its film strength by improving theelongation characteristics of films of the ink.

Re=presentative classes of useful flexibilizers are selected from thegroup consisting of synthetic resins that are free from vinyl chlorideunits and that have a 20% elongation temperature of less than about 85°C., and plasticizers for polyvinyl chloride.

Specific examples of useful vinyl chloride-free resins include ethyl,methyl, and butyl methacrylate homopolymers, and copolymers of saidhomopolymers with methyl, ethyl, and butyl acrylate. Such resins areavailable from Rohm and Haas as the Acryloid® series and from DuPont asthe Lucite® series.

Other useful vinyl-chloride-free resins are urethane polymers such aspolyester-functional aromatic urethanes (e.g., the Estane® series fromB. F. Goodrich), and polyester and polyether-functional aliphaticurethanes (e.g., respectively QI-12 and PE-192 from Quin).

Other useful thermoplastic resins include linear polyester resins (e.g.,Vitel® PE-222 from Goodyear), acrylonitrile-butadiene-styrene resins(e.g., Cycolac® WA 2021 from Borg-Warner), polycaprolactam polymers(e.g., PCL-700 Union Carbide, sucrose acetate isobutyrate, available asSAIB from Eastman Chemical, ethylene vinyl acetate resin, ethylmethacrylate, and butyl methacrylate resin. Combinations of vinylchloride-free thermoplastic resins may be utilized if desired.

Specific examples of classes of plasticizers useful in the compositionsof the invention are alcohol phthalates (e.g., Santicizer® 711, amixture of alcohol phthalates containing from 7 to 11 carbons in thephthalate chain from Monsanto); polymeric polyesters (e.g., Santicizer®429, available from Monsanto); aromatic phthalates (e.g., Santicizer®160, butyl benzyl phthalate from Monsanto) and mixed lower alkyl benzylphthalates (Santicizer® 261 from Monsanto); epoxidized vegetable oils(e.g., epoxidized linseed oil, epoxidized soybean oil, epoxidizedsafflower oil); and phosphoric acid derivatives (e.g., Santicizer® 141,2-ethylhexyl-diphenyl phosphate from Monsanto), and tricresyl phosphatefrom Monsanto.

Blends of flexibilizers e.g., combinations of one or more resins withone or more plasticizers, may be employed if desired.

Colorants useful in the compositions of the invention comprise up toabout 40% by dry weight of the composition. Preferably they comprisefrom about 1% to 30%. Quantities of from about 1% to 15% are useful inproviding light and pastel shades while quantities of from about 15% to30% are useful in providing dark colors. The colorants may be selectedfrom dyes or pigments, although pigments are preferred.

Examples of useful pigments include

Molybdate Orange

Primrose Yellow

Quinacridone Red

Phthalocyanine Blue

Carbon Black

Phthalocyanine Green

Rutile Titanium Dioxide

Carbazole Violet

Chrome Yellow

Irgasine Yellow

Lead Chromate Yellow

Quinacridone Pink

The pigments may be provided in dry bulk form, or as a dispersion in asolvent, liquid or solid resin, plasticizer, or combinations thereof.

A variety of other ingredients may be utilized in the compositions ofthe invention. Thus, for example, ultraviolet light absorbers, heatstabilizers, surfactants to aid application of the composition to acarrier, and solvents may be employed. Examples of materials useful forthese purposes are known as will be understood as a result of thisdisclosure.

As discussed above, the compositions useful in the present invention areprepared by dissolving the ingredients together in an appropriatesolvent. The solution is then filtered and coated onto a suitablecarrier. Coating is preferably carried out by screen printing. Othercoating techniques, such as reverse roll, knife, and rotogravure, may beutilized if desired. The solvent is removed from the coated layer by,for example, impinging the coating with air at about 80° C.

The thickness of the dry layer of thermally-transferable ink is notcritical to the invention. However, it has been found that good results,in terms of transferred indicia quality, may be obtained if the layerhas a thickness in the range of 5 to 50 microns. Preferably thethickness is in the range of 8 to 25 microns. Most preferably thethickness is about 25 microns.

The carrier utilized in the transfer sheet may be any material that isdimensionally stable and exhibits high release characteristics. Thus,the carrier must release from the thermally-transferable ink once it hasbeen adhered to a receptor. The carrier usually is coated or impregnatedwith a suitable release material so as to facilitate this release. Thecarrier preferably is flexible and exhibits good hand, that is, it maybe cut easily by die cutting or hand cutting techniques.

Sheeting materials that have suitable release characteristics are known.They include Warren O-Duplex, available from S. D. Warren Paper Co.;Trans-Eze® 2000 and 3000, and Kimdura, all available fromKimberly-Clark; polyethylene sheeting, and polypropylene sheeting.Silicone or other treated paper may also be employed.

The thermally-transferable ink may occur on the carrier in a variety ofways, including, for example, as a continuous layer of the ink or as oneor more discrete indicium. The former type of transfer sheet may be usedto provide large background areas or individually prepared indicium onsign faces. The latter type of transfer sheet may be used in applyingpre-prepared indicium to a receptor.

In the process of transferring thermally-transferable ink, especially toform sign faces, described herein it is preferable, though notnecessary, to apply a clear (i.e., colorless and transparent) layer overthe indicium-bearing surface. The clear layer is most preferably thin(i.e., approximately 25 microns) and clear layer acts as a barrier tothe loss of flexibilizer (especially plasticizer). Additionally, itreduces the ability of nutrients to come to the surface thereby reducingthe growth of fungus. Still further, it serves as a moisture barrier.Furthermore, it can contain other additives such as ultraviolet lightabsorbers, antioxidants, fungistats, and so forth.

The clear coat may be applied by the same techniques used to transferthe ink from the carrier to the receptor. Like the ink, the clear coatis preferably provided on a material that exhibits high releasecharacteristics. Common processing techniques can be utilized to applythe clear coat to a release material.

A useful clear coat comprises at least 95% by weight of acrylic polymerssuch as polymethyl methacrylate, and copolymers of methyl methacrylatewith ethyl and butyl methacrylate. The remaining 5% by weight is made upof other additives such as those mentioned above. Examples of thesematerials include the 3900 and 4000 series of Scotchcal® resinsavailable from 3M Company.

Known thermoplastic compositions may also be employed to provide thethermally-transferable ink in the process of the present invention.However, these materials must be combined with a flexibilizer if theyare to have a combination of a 20% elongation temperature less thanabout 85° C. and an elongation at break of at least 15%. Examples ofsuch commercially available formulations include the 600 Series inksfrom General Formulations (a division of General Research Incorporated),the G.V. series inks from Naz Dar, the 9600 series inks from ColonialInks, the "Lov" series from Advance Screen Printing Co., and the 8000series vinyls from Tibbetts & Westerfield.

The present invention is further described in the following exampleswherein all percentages are by weight unless otherwise indicated.

EXAMPLE 1

Thermally transferable ink formulations were prepared from the followingingredients using the quantities indicated.

    ______________________________________                                                                 %                                                    ______________________________________                                        Polyvinyl Chloride-Polyvinyl Acetate Copolymer                                                           18                                                 (Bakelite ® VYHH from Union Carbide,                                      86% vinyl chloride and 14% vinyl acetate)                                     Polymethyl Methacrylate-Ethyl Methacrylate                                                               4                                                  Copolymer (Acryloid ® B82 from Rohm and Haas)                             Aliphatic Urethane (QI 12 from K. J. Quin)*                                                              4                                                  Butyl Benzyl Phthalate (Santicizer ® 160                                                             7                                                  from Monsanto)                                                                Mixed Alkyl Benzyl Phthalate (Santicizer ® 261                                                       7                                                  from Monsanto)                                                                Quinacridone Red           10                                                 2,2-dihydroxy-4,4-dimethoxy benzophenone                                                                 0.1                                                Ba & Cd Stearate           0.25                                               Epoxidized Linseed Oil     0.5                                                Isophorone                 25.1                                               Butyl Cellosolve           7.75                                               Mixed aromatic solvents (SC solvent 150 from                                                             5.1                                                Central Solvents and Chemicals)                                               Diacetone Alcohol          7.1                                                Cyclohexanone              4.1                                                ______________________________________                                         *Provided in solution, solvent evaporated and dry urethane added.        

The ink solution was prepared by mixing all ingredients together untilthey had dissolved and the pigment had dispersed. The pigment wastprovided in a dispersion in cyclohexanone before addition.

The solution was then applied to the release surface of a carrier ofTrans-Eze® 2000 and dried at 60? C. to remove the solvent. The thicknessof the dried layer was 25 microns. The ink composition hasd a 20%elongation temperature of 82° C. and an elongation at break of 110%.

The resulting dry transfer sheet was applied to the surface of apolyvinyl chloride sheet that was reinforced with thermoplastic fibersso that the thermally-transferable ink contacted the polyvinyl chloridesheet. The surface of the polyvinyl chloride sheet wasthree-dimensional. The resulting intermediate structure was placed in avacuum frame and adjusted to remove all wrinkles. The frame was thenclosed and the pressure therein reduced to 0.2 atmosphere after whichthe temperature therein was raised to 88° C. This pressure andtemperature were maintained for 2 minutes. The pressure was thenincreased to atmospheric pressure and the temperature in the vacuumframe was lowered to 50° C. The carrier was then stripped-from thereceptor. The ink transferred completely from the carrier to thereceptor. The carrier left no residue on the indicia. When the tapeadhesion test was performed on the transferred ink, a classificationnumber of 5 was obtained (i.e., no ink was removed from the receptor).

EXAMPLES 2-5

Thermally-transferable ink formulations were prepared and coated ontoTrans-Eze® 2000 carrier as described in Example 1 from the followingformulations. All quantities are in %.

    ______________________________________                                                       2    3        4      5                                         ______________________________________                                        Bakelite ® VYHH                                                                            18     18       25   25                                      Acryloid ® B82                                                                             4      4        --   --                                      Sucrose Acetate Isobutyrate                                                                    4      4        --   --                                      Santicizer ® 711 (mixture of                                                               7      7        --    6.25                                   alcohol phthalates from                                                       Monsanto)                                                                     Santicizer ® 261 (Aromatic                                                                 7      7        --   --                                      Phthalate Plasticizer from                                                    Monsanto)                                                                     Phthalocyanine Blue                                                                            8      --       --   --                                      Rutile Titanium Dioxide                                                                        0.5    --       --   --                                      Carbazole Violet 1.5    --       --   --                                      Quinacridone Red --     8        --   --                                      Molybdate Orange --     2        --   --                                      2,2-dihydroxy-4,4-dimethoxy-                                                                   0.4    0.4      --   --                                      benzophenone                                                                  Ba & Cd Stearate 0.5    0.5      --   --                                      Epoxidized Soy Bean Oil                                                                        1      1        --   --                                      Dimethoxy Silicone (SF-96                                                                      0.1    0.1      --   --                                      from General Electric)                                                        Isophorone       30     30       --   --                                      Butyl Cellosolve 8      8        --   --                                      Mixed aromatic solvents (SC                                                                    10     10       --   --                                      solvent from Central                                                          Solvents and Chemicals)                                                       Cyclohexanone    --     --       75   68.75                                   ______________________________________                                    

The ink compositions had respective 20% elongation temperaturs of 71°C., 71° C., 85° C., and 84° C. and elongations at break of 130%, 130%,0% and 95%.

The ink compositions of the resulting transfer sheets were transferredto a Panaflex® receptor as described in Example 1 at varioustemperatures. The pressure was 0.2 atmosphre. It was found that atemperature of only 82° C. was sufficient to transfer the inkcomposition of Example 2. A classification number of 5 was obtained inthe tape adhesion test. The ink compositions of Examples 3-5demonstrated the classification number when transferred at a temperatureof about 88° C.

When the composition of Example 4 was transferred as described above toa seam, it was found that the tape adhesion classification number wasless than 4 for that portion of the ink on the seam. This demonstratesthat while many ink compositions may be transferred according to theprocess of the invention, those of the invention provide superiorresults.

We claim:
 1. A dry, adhesive-free process for transferring a drythermally-transferable ink composition from a carrier to a receptorcomprising the steps of:(a) providing a receptor and a carrier bearing adry thermally-transferable ink composition and a vacuum frame having avacuum bed, a top capable of covering the vacuum bed, a porous materialon said top for contacting said carrier, and a source of heat above saidporous material; (b) placing said receptor and said carrier on saidvacuum bed so that said ink composition contact said receptor to form aninterface therebetween; (c) adjusting said interface so that it is freefrom any wrinkles and closing said top so as to form a chamber; (d)evacuating substantially all of the air from said interface by means ofvacuum to create a reduced pressure in said chamber and coform said inkcomposition to said ink composition to said receptor; (e) mantainingsaid reduced pressure and heating said ink composition and said receptorto a temperature, and for a time, sufficient to soften said inkcomposition, fuse said ink composition to said receptor and form anintimate bond thereto and transfer said ink from said carrier to saidreceptor; and (f) removing said carrier from said ink, thereby leavingsaid ink adhered to said receptor surface.
 2. A process according toclaim 1 comprising the further step of cooling said ink and saidreceptor to a temperature sufficient to harden said ink and cause theadhesion of said ink to said receptor to be greater than the adhesion ofsaid ink to said carrier.
 3. A process according to claim 2 wherein saidink and said receptor are cooled to a temperature of less than about 65°C.
 4. A process according to claim 1 wherein heating is carried on at atemperature in the range of about 75° C. to 110° C.
 5. A processaccording to claim 4 wherein heating is carried on for from about 2 to 5minutes.
 6. A process according to claim 1 wherein said reduced pressurein said chamber is at most about 0.75 atmosphere.
 7. A process ofmanufacturing a sign face having a thermally-transferable inkcomposition applied to at least a portion of a receptor in a dry,adhesive-free manner, said process comprising the steps of:(a) providinga receptor and a carrier bearing a layer of a dry thermally-transferableink composition and a vacuum frame having a vacuum bed, a top capable ofcovering the vacuum bed, a porous material on said top for contactingsaid carrier, and a source of heat above said porous material; (b)placing said receptor and said carrier on said vacuum bed so that saidink composition contacts said receptor to form an interfacetherebetween; (c) adjusting said interface so that it is free from anywrinkles and closing said top so as to form a chamber; (d) evacuatingsubstantially all of the air from said interface by means of vacuum tocreate a reduced pressure in said chamber and conform said inkcomposition to said receptor; (e) maintaining said reduced pressure andheating said ink composition and said receptor surface to a temperature,and maintaining said temperature for a time, sufficient to soften saidink composition, fuse said ink composition to said receptor surface andform an intimate bond thereto and transfer said ink composition to saidreceptor surface; (f) cooling said ink composition and said receptorsurface to a temperature sufficient to harden said ink composition andcause the adhesion of said ink composition to said receptor surface tobe greater than the adhesion of said ink composition to said carrier;and (g) removing said carrier from said ink thereby leaving said inkadhered to said receptor surface.
 8. A process according to claim 7wherein said receptor is polymeric.
 9. A process according to claim 8wherein said receptor is rigid.
 10. A process according to claim 8wherein said receptor is flexible.
 11. A process according to claim 8wherein said receptor comprises polyvinyl chloride sheeting.
 12. Aprocess according to claim 11 wherein said receptor is fiber reinforced.13. A process according to claim 12 wherein said fiber is thermoplastic.14. A process according to claim 13 wherein said receptor has a threedimensional surface.
 15. A process according to claim 7 wherein saidreceptor has a smooth surface.
 16. A process according to claim 7wherein said receptor has a three dimensional surface.
 17. A processaccording to claim 1 wherein said thermally-transferable ink compositioncomprises(a) from about 50 to 95% by weight of a thermoplastic polymerselected from the group consisting of polyvinyl chloride and copolymersthereof; (b) from about 50 to 5% by weight of a flexibilizer for saidthermoplastic polymer that is compatible with said thermoplasticpolymer; and (c) up to about 40% by weight of a colorant; wherein saidcomposition has a 20% elongation temperature of less than 85° C. and anelongation at break of at least about 15%.
 18. A process according toclaim 17 wherein said thermoplastic polymer is selected from the groupconsisting of polyvinyl chloride and polyvinyl chloride-polyvinylacetate copolymers.
 19. A process according to claim 17 wherein saidflexiblilizer is selected from the group consisting of synthetic resinsfree from vinyl chloride units having a 20% elongation temperature ofless than about 85° C., and plasticizers for polyvinyl chloride.
 20. Aprocess according to claim 19 wherein said flexiblilizer is selectedfrom the group consisting of ethyl, methyl, and butyl methacrylatehomopolymers, and copolymers of said homopolymers with methyl, ethyl,and butyl acrylate, polyester-functional aromatic urethanes, polyesterand polyether-functional aliphatic urethanes, linear polyester resins,acrylonitrile-butadine-styrene resins, polycaprolactam polymers, sucroseacetate isobutyrate, ethylene vinyl acetate resin, ethyl methacrylate,butyl methacrylate, alcohol phthalates, polymeric polyesters, aromaticphthalates, mixed lower alkyl benzyl phthalates, epoxidized vegtableoils, phosphoric acid derivatives, and tricresyl phosphate.
 21. Aprocess according to claim 17 wherein said colorant is a pigment.
 22. Aprocess according to claim 7 or 17 wherein said heating is carried outat a temperature in the range of about 75° C. to 110° C.